When a permanent magnet synchronous motor is driven by vector control, accurate position information of a rotor thereof is required. A resolver may be used to recognize the absolute position of the rotor. However, an unbalance of a magnitude of a signal may occur due to a difference in transformation ratios of the resolver, unbalanced excitation signals, non-uniform inductance components, and distortion from a signal-processing circuit, and thus error components may periodically occur in the position information. Therefore, motor control performance is deteriorated, and thus, the use of motor in fields requiring high performance is limited.
Since such an error component may periodically occur, it can be expressed as sine or cosine function having an arbitrary magnitude and phase as follows.Nth position error=Magnitude*Cos(Nwt−Phase)
Here, in the criterion for sorting orders based on the electrical angle, an electrical angle of 0 to 2 pi is counted as one period.
Conventionally, a method for compensating for position error of a resolver using an RLS adaptive filter is provided, but is limited in its ability to provide compensation for a position error throughout a full speed range.
Further, conventional methods for compensating for position error cannot diagnose position error corresponding to the case where a false position error of the resolver is learned due to intermittent signal abnormality, vehicle vibration, and the like. Therefore, the reliability of the position error compensation apparatus cannot be guaranteed.
Therefore, there is a need for a solution that can diagnose the possibility of false compensation for the current position error so as to improve the reliability and stability of the position error compensation apparatus.
The above description in this background section is only for improving understanding of the background of the present disclosure, and should not be taken as an acknowledgement indicating that the information forms a prior art that is already known to a person skilled in the art.